1. Field of the Invention
The present invention relates to a printing system, a job processing method, a storage medium, and a printing apparatus.
2. Description of the Related Art
In the printing industry, conventionally, a print product is issued after various operations and processing are performed. The various operations and processing include, for example, input of an original document, designing of the original document, editing of a layout, a comprehensive layout (presentation by printing), proofreading (correction of the layout and color), proof printing, generation of block copy, printing, post-processing, and dispatching.
In the conventional printing industry, an offset platemaking and printing machine has been used. Accordingly, it is necessary to perform processing for generating a block copy. However, once a block copy is generated, it is not easy to correct the generated block copy. Thus, correction of a block copy requires high costs.
Accordingly, in generating a block copy, intensive proofreading (namely, close checking of a layout and colors) is required. Thus, a long proofreading time may be required before a print product is issued. Furthermore, a large-scale apparatus is used in each processing and a user (operator) of the apparatus is required to have an exclusive professional knowledge. Thus, a skilled user having knowledge about how to operate the large-scale apparatus is required in operating such apparatus.
Under these circumstances, in recent years, a Print On Demand (POD) printing system utilizing an electrophotographic printing apparatus or an inkjet printing apparatus has been proposed (see Japanese Patent Application Laid-Open NO. 2004-310746 and Japanese Patent Application Laid-Open NO. 2004-310747). Using such a POD printing system, processing for generating a block copy and other complicated operations become unnecessary.
However, in marketing such POD printing systems, there are some matters to be considered and solved.
For example, in a printing system for the POD market, improvement of the productivity has been regarded as important. In marketing products for the POD market, it is considered important to prevent downtime from occurring.
In this regard, a conventional printing system includes an auto cassette change (ACC) function. With the ACC function, after paper sheets necessary for printing and stacked in a paper feed unit are completely consumed, the print operation can be continued using paper sheets in another paper feed unit.
In a printing system having the above-described configuration, the following operation, for example, can occur.
(1) In order to feed paper necessary for a print operation, the printing system attempts to pick up paper sheets from a paper feed unit.
(2) As a result, the printing system detects that no paper is present in the paper feed unit.
(3) According to the detection result, after completely performing printing on the paper sheets being printed and discharging the printed paper to the outside of the printing machine, the printing system suspends the printing operation.
(4) Subsequently, the printing system searches for another paper feed unit to continue a printing operation and then feeds paper sheets from the other paper feed unit to continue the printing operation.
As described above, in a conventional printing system, downtime arises, in which a printing operation temporarily stops during a time period from detection of running out of paper sheets to restart of the printing operation.